KHALIFA UNIVERSITY RESEARCHES SUSTAINABLE FUEL FOR AVIATION IN

Dr. Steven Griffiths

Khalifa University Senior Vice-President, Research and Development, and Professor of Practice, Research and Development

Steve Griffiths Senior Vice-President, Research and Development, and Professor of Practice at the Khalifa University of Science and Technology, is representing the university in one of the biggest programs for research into renewable and advanced fuel technologies for Aviation in UAE.

The program is the first of its kind and brings together policymakers, regulators, fuel producers, academia and researchers, as well as aircraft and power plant manufacturers including airline operators. It includes names, such as ADNOC, Boeing, Emirates, ENOC Group, Etihad, Honeywell, Khalifa University, and Masdar.

The program has been established as a consortium aimed at developing a center called Air-CRAFT (UAE Centre for Renewable and Advanced Fuel Technologies for Aviation). The Air-CRAFT initiative is endorsed by the UAE Ministry of Energy and Infrastructure, as well as the General Civil Aviation Authority. It is focused on developing, producing, and scaling sustainable aviation fuel (SAF) technologies.

Air-CRAFT is a regionally first-of-its-kind initiative that brings together entities across the value chain, industrial policy makers, aviation regulators, fuel producers, academia and researchers, aircraft, power plant manufacturers, airline operators as well as international entities.

This is part of UAE’s efforts to reach net zero by 2050. Air-CRAFT will support the decarbonization of the aviation sector, which is a key sector for the UAE given that the country is a global hub for long-haul international aviation.

Research topics for Air-CRAFT will include environmental impact assessments, feedstock and process optimization, techno- economic assessments and research into the production of alternative fuels for the aviation sector.

As per Griffiths, Khalifa University places the UAE’s energy transition at the core of its strategy. He stated, “Given the critical importance of aviation to the UAE economy, the Air-CRAFT initiative, aligns seamlessly with Khalifa University’s research agenda, is of considerable importance. Khalifa University looks forward to serving as the cornerstone of Air-CRAFT’s research, technology development and human capital development activities.”

Griffiths is the Principal Investigator for the program at Khalifa University and engaged in the steering committee overseeing the development of Air-CRAFT.

Alternative Fuels

In terms of the aviation industry, alternative fuels are central to decarbonization, and sustainable aviation fuels (SAF) are the cornerstone. These fuels can be derived from non-petroleum feedstocks, like municipal waste, used cooking oil, agricultural residues, forestry waste, algae and more.

In addition to those are what are known as electro fuels, power-toliquids (PtL), or synthetic fuels which are produced from hydrogen (from water electrolysis) and captured carbon dioxide, using renewable electricity.

Griffiths explains that the alternative fuels being looked into for long-haul aviation are mainly drop-in replacements for fossil-based jet fuel. The alternative fuels can be carbon-neutral if renewable energy is used for hydrogen production, although the carbon dioxide produced from combustion also needs to be considered and accounted for properly. Carbon-neutrality is best achieved when the carbon dioxide used in fuel production is captured directly from the air.

Griffiths explains, “Drop in fuels are seen as an option for hard to electrify transport sectors like aviation, shipping, and long-haul trucking. Drop-in fuels that can be blended with conventional jet fuel at varying ratios require no changes to aircraft, engines, or fueling infrastructure.”

In addition, the lifecycle carbon emissions from drop in fuels are typically 50-80% less than conventional jet fuel.

According to Griffiths there are seven approved production pathways with more in development. The most common production pathways in existence are Fischer-Tropsch, and hydroprocess esters and fatty acids (HEFA).

To date they only make up less than 0.1% of total jet fuel use, however numerous airlines have pledged to ramp up adoption.

Griffiths believes that while other sources of fuel or aircraft, including hydrogen and electricity from batteries are relevant for certain applications, SAF (Sustainable Aviation Fuel), which is the focus of Air-CRAFT, will be the decarbonized fuel technology required in flight routes where direct electrification or hydrogen use are not considered technically feasible.

Even in the long run, flights covering routes of distances greater than or between 3,500 km to 4,000 km will need energy-dense fuels like SAF. Such long-haul routes typically are served by high passenger count airframes powered by turbofan engines and are a key source of global carbon emissions from aviation.

Implications on Future Space Fuels

In terms of utilization of alternative fuels for space activities, Griffiths says that hydrogen has a role to play but not necessarily in SAF.

He states, “Yes, hydrogen has a fuel role in space, but we are not working on space fuels in Air-CRAFT. For space, liquid fuels would be, for example liquid hydrogen and liquid oxygen which are used for many rockets today. These are clean burning fuels that operate robustly under the conditions required for space applications.”

Effect of Sustainable Fuels in other sectors

Aviation is one of the foundational elements of globalization, and sustainability should be a part and parcel of its growth.

In 2019, the global aviation sector accounted for 914 Mt (metric tons) of CO2 emissions, which represented 2.1% of all anthropogenic CO2 emissions. In 2022, global CO2 emissions from aviation reached approximately 80% of 2019 levels, and preliminary data for 2023 indicate that passenger numbers are back to pre-pandemic levels.

As such Griffiths believes that the move toward decarbonization of aviation achieving net-zero by 2050 will require a portfolio of options, including novel aircraft designs (engines, airframes, etc.), operational improvements and new infrastructure, aimed at addressing both CO2 emissions and non-CO2 effects.

In conclusion, SAF plays a key role in decarbonization of the aviation sector, especially towards meeting early emissions reduction targets.

While the current aspiration is for 449 billion liters of SAF to be produced in 2050, less than 0.1% of this amount, or roughly 300 million liters, was produced in 2022.

This implies that more than a 1,500-fold increase in SAF production is needed in just under 27 years, which translates into roughly 5,000–7,000 new production facilities, requiring a considerable global investment that could amount to as much as $1.1–1.45 trillion.